1. Field of Invention
This invention pertains to pre-cast retaining walls. More particularly, this invention pertains to an apparatus for manufacturing pre-cast cementitious retaining walls such as reinforced concrete retaining walls.
2. Description of the Related Art
Retaining walls are commonly used in a wide variety of construction, civil engineering, and landscaping applications, for example, to support earth, rock, sand, and other such materials forming slopes and embankments (hereinafter “embanked materials”) and to limit down-slope movement, such as erosion, landslides, etc., of the embanked materials. Retaining walls are commonly formed by constructing a substantially rigid wall in front of an embankment and then placing and compacting soil or other fill (hereinafter “backfill”) behind the wall to allow the wall to support the embanked materials in the configuration of the embankment.
One common method of constructing a retaining wall is to form the retaining wall from reinforced concrete which is poured in place at the location of the finished retaining wall. For example, in a traditional cantilevered retaining wall, a poured-in-place steel-reinforced concrete structural footing is constructed along the base of an embankment to extend horizontally along the embankment. Thereafter, concrete forms are erected above the structural footing, and a panel of steel-reinforced concrete is poured in place and integrally formed with the footing to extend upward across the surface of the embankment to form a wall. After the concrete has properly cured, the concrete forms are removed, and backfill is placed between the finished retaining wall and the embankment. The traditional cantilevered retaining wall then functions by cantilevering loads from along the wall panel to along the length of the structural footing so as to convert horizontal loads imparted to the wall panel from the embankment to vertical loads along the ground beneath the footing.
In constructing poured-in-place concrete retaining walls, problems arise in the difficulty of labor, time, and expense associated with erecting the concrete forms, pouring the concrete in place, and allowing the concrete to properly cure prior to removing the forms and backfilling the embankment. In several situations, erosion and/or landslides of the embanked materials occur prior to completion of the poured-in-place concrete retaining wall. Moreover, the concrete surfaces of traditional poured-in-place concrete retaining walls are often viewed as unsightly and not aesthetically pleasing.
Thus, in recent years, masonry units such as stone blocks, concrete masonry units, bricks, and the like have gained wide popularity for use in fabricating retaining walls having an aesthetically attractive appearance. It is well-known in the art to fabricate such masonry retaining walls either by arranging the masonry units in a stacked configuration to form a wall along the surface of the embankment or by joining the masonry units in the stacked configuration using a cement binder. Masonry units suitable for use in fabricating retaining walls are typically weighted such that the finished retaining wall exhibits a weight capable of resisting capsizing due to horizontal loads placed along the retaining wall by the embanked materials, thereby retaining the embanked materials substantially within their embanked configuration.
Though retaining walls fabricated from masonry units are often considered more attractive than reinforced concrete retaining walls, a wall fabricated from masonry units is typically not as structurally sound as a reinforced concrete wall of similar size and weight. Thus, masonry retaining walls must typically be constructed of thicker and often heavier materials than reinforced concrete retaining walls of similar structural strength. Furthermore, in situ construction of masonry retaining walls is also labor intensive, often requiring significant time and expense. Thus, it is not uncommon for erosion and/or landslides of the embanked materials to occur prior to completion of a masonry retaining wall.
In the reinforced concrete industry, pre-cast reinforced concrete structures, such as pre-cast reinforced concrete beams, columns, slabs, etc., are known in the art. Such pre-cast concrete structures allow a builder to pour concrete into a desired shape and allow the concrete to cure in a location removed from the finished concrete structure. Thereafter, when the pre-case concrete structure is needed for building construction, it is brought to the location of the construction and quickly placed in the desired finished location. In this manner, the time and labor associated with forming, pouring, and curing pre-cast concrete occurs prior to the on-site construction process, thereby increasing the speed with which such pre-cast concrete structures can be utilized.
Accordingly, there is a need to fabricate a pre-cast concrete retaining wall which is capable of exhibiting the strength-per-unit-thickness of a reinforced concrete retaining wall along with the aesthetically pleasing appearance of a masonry retaining wall, and which can be transported to the site of an embankment for speedy placement at a desired location to serve as a retaining wall.